Parley Parker Pratt, Sr. (1807-1857) was an early leader of The Church of Jesus Christ of Latter-day Saints. He was baptized in September 1830 and a few weeks later baptized his brother Orson; the two were among the first members of the Quorum of the Twelve Apostles called in 1835. Pratt was an indefatigable missionary. He helped open up missionary work in England and the Pacific Isles. A staunch defender of plural marriage, he was murdered in 1857 by the ex-husband of one of his plural wives. Pratt's writings include The Voice of Warning and The Key to the Science of Theology, which remained standard expositions of LDS doctrine through the 20th century. Numerous hymns in the current LDS hymnal were penned by Pratt, and his Autobiography, completed shortly before his murder, is an important source of information on early LDS history as well as an entertaining account of the life of a remarkable man. This book is in the Deseret Alphabet, a phonetic alphabet for writing English developed in the mid-19th century at the University of Deseret (now the University of Utah).